Lawn mower



Sept. 3; 1935. H. L. BLYDENBURGH LAWN MOWER Filed Nov. 15

, 1933 4 Sheets-Sheet 1 INVENTOR ATTORNEYS Sept. 3, 1935.

H. L. BLYDENBURGH LAWN MOWER Filed Nov. 15, 1933 4 Sheets-Sheet 2INVENTOR ATTORNEYS Sept; 3, 1935 H. BLYDENBURGH LAWN MOWER Filed Nov.15, 1933 4 Sheets-Sheet 3 Ill 7 INVENTOR ATTqBNEYS Sept. 3, 1935.

H. L. BLYDENBURGH LAWN Mowmi- Filed Nov. 15, 1935 4 Sheets-Sheet 4ATTORNEYS J Patented Sept. 3, 1935 LAWN MOWER Harold L, Blydenburgh,Detroit, Mich, assignor to The Moto-Mower 00., Detroit, Mich, acorporation of Michigan Application November 15, 1933, Serial No;698,160

' 20 Claims. (Cl. 56-26) This invention relates to improvements in lawnmowers, pertaining more particularly to machines of this type driven bypower.

Lawn mowers operated through ground wheel drive, are generally ofcomparatively narrow width of cut and readily manipulated in service.The desirability of being able to cut a comparatively wide zone has ledthe development of the art in the direction of utilizing motive power asa drive power source, a suitable internal combustion motor mounted onthe frame of the. mower being usually employed, the ground wheels andthe L cutting reel or reels being driven thereby through suitable driveconnections. Because of the weight of the power unit, the overalldimensions of the frame are fairly large, and hence the addition of thecutting unit to such main supporting frame provides a dimensionalcharacteristic such as to make it advantageous to mount the cutting unitmovable bodily relative tothe frame to permit suflicient flexibilitybetween the power and cutting units as to enable the latter operatingproperly with respect to the grass to be out without being materiallyaffected by the power unit rolls when travelling over undulatingsurfaces. It is point support for the cutting unit, to prevent thelatter from moving out of position to provide the propercut; where suchforms are used, two of the supports are generally in the form of castorwheels, located at the front, the rear support being a shoe or a pair ofshoes properly positioned. -Since the castor wheels are in front oftheline of cut, they must travel over the uncut grass and thus have atendency to turn down the grass and 45 affect the clean cutting. Thesame condition is osition, or shoes alone be employed, the feature inthis respect being that supports must be placedin advance of the line ofcut 'as well as in rear,

50 since the presence of the support at front or rear alone would permitthe frame to rotate on its axis and thus affect the position of thecutting knife.

It is therefore desirable to limit the cutting :gresent if the wheelsand shoes are reversed in .55 unit support to a position rear'ofthe lineof cut, but this necessitates the use of some means for preventingrotation of the cutting unit frame on its axis. Various expedients havebeen proability in the height of the cutting knife, so as to regulatethe depth of out, etc. Generally, these 10 linkage structures are moreor less complicated and of such arrangement as to make it more or lessdifflcult to obtain adjustments, etc.

The present invention is designed to limit the cutting unit support to aposition in rear of the 1 line of out, and retain the cutting frameagainst free rotation on its axis, by the use of linkage which presentscharacteristics of a parallelogram, the connecting links forming thesides of the figure with the power unit and cutting unit framesproviding the ends of the figure, each link having a pivotal connectionat both ends. As a result, the position of the cutting knife remainspractically constant relative to the unit axis during the swing of theunit, although the swing itself is on two individual arcs whichintersect.

By permitting adjustability in the length of one of the links, the framecan be swung on its axis to change the angularity of the cutting knifeand thus regulate the depth of the cut. The parallelogram is arrangedangular to a horizontal plane, and through the link length and suchangularity, the cutting edge remains practically constant as to depthwhen travelling over undulating surfaces. 3

The linkage also permits ready positioning of the cutting unit in aninoperative position to permit the ready transportation of the mower,suitable holding structures being' provided for the purpose. 40

The mower includes a number of other features specifically referred .tohereinafter and which form objects of the present invention.

To these and other ends, the nature of which will be more clearlyunderstood as the invention is hereinafter disclosed, said inventionconsists in the improved construction and combinations of partshereinafter fully described, illustrated in the accompanying drawings,and more particularly pointed out in the appended claims.

In the accompanying drawings, in which similar reference charactersindicate similar parts in each of the views,

Figure 1 is a side elevation of a lawn mower disclosing the presentinvention; w

Fig. 2 is a detail view taken on line 2-2 .of Figure 1;

Fig. 3 is a fragmentary view taken on line 3-'-3 of Figure 1;

Fig. 4 is a plan view, parts being omitted for the purpose of clearness;

Fig. 5 is a detail sectional view taken on line 5-5 of Figure 1;

. Fig. 6 is a sectional view taken on line 6-6 of Figure 1;

Fig. '7 is a detail sectional view taken on line 'l'l of Figure 6;

Fig. 8-is a detail sectional view taken on line 8,8 of Figure 7; and

9 is a detail sectionalview taken on line 9-9 of Figure 1.

Figs. 10 to 15, inclusive, are a series of views, -diagrammatic in form,and which present-portions of the mower in general side elevation,presenting various relationships of the several units in service andunder varying ground surface conditions.

Fig. 16 is a view of similar type but showing the cutting unit in itsraised position.

For the purpose of illustrating the present invention, the same has beenshown in connection with structures which form parts of a wellknownpower lawn mower, shown more or less in detail, the description of.which, however, is presented in general form, the disclosure beingdesigned as more or less illustrative of structures generally of thistype.

The power unit includes a ground roller formation A divided into twoparts a a these being connected by a suitable differential structure (1'(Figs. 6, '7 and'8) these being mounted on ashaft a2 mounted on a frameB which constitutes the power unit frame, and on which is mounted asuitable motor ,C, shown as of the internal combustion engine type, andwhich includes a drive shaft 0. The frame B carries a counter-shaft b,driven from shaft cby a suitable drive connection, shown as a chaindrive 0', 'shafts b and a2 having a similar chain drive connection (13.The frame B also carries a forward roller D, rollers A and D forming thetravelling support for the power unit. The usual control structures forcontrolling motor operation and activity and inactivity of the roller Aare not referred to in detail, since they are usual with mowers of thistype. The frame has the usual rearwardly-extending steering structure22'.

The shaft b also forms the drive for the cuttingunit, the shaft having aclutch structure b2, controlled through the manipulation of a handle b3mounted on rod b4, the clutch being adapted to engage and disengage asleeve b5 mounted on shaft 1) and which carries the drive sprocket forthe chain drive b6 which leads to the sprocket carried by the shaft 6 ofthe cutting reel 6 which form parts of the cuttingunit E, shaft e beingmounted in side members In of a frame of this unit, the latter beingcompleted by a cross-rod l I, and a cross-bar I2, located respectivelyto the front and rear of a vertical plane extending through the axis ofshaft e. The cross-bar l2 carries the stationary cutting member l3, aswell as a shoe or shoes I4, depending on whether it is desired to havethe shoe extend the full width of the cut or be in the form of a pair ofshoes in the end zones of the cut. The cross-bar I2 is supported by themembers l0 adjustably, an arm l2a at the ends of the bar being oppositea portion Illa of the periphery of a member ID, the arm and member beingconnected by a bolt or screw [2b, with the rm carrying adjusting membersI20 adapted 0 contact with said member portion, thus permittingadjustment of the arm toward and from the member, each end of thecross-bar being similarly equipped. This permits the knife to beadjusted relative to the travel path of the reel cutting edges.

The cutting unit is located in advance of the power unit, and isdesigned to be swingable relative thereto. This result is obtained byconnecting the cutting unit to the frame B at each end of the cuttingunitfthe connections at each end being in the form of two links l5 andHi, the forward end of link l5 being pivotally mounted on shaft e, whilelink l6 has its forward end connected to the side member Ill above thepath of travel of the cutting reel. The rear end of link I5 is connectedto frame B in advance of but adjacent to shaft b.

As shown in Fig. l ,'the shoe l4 and the rollers A and D are located inan approximately horizontal plane representing the surface of the lawn.The dimensions of the cutting unit are such that in such position thecutting knife [3 and cutting reel are in approximately the desiredlocations. This places the shaft 6 on a lower plane horizontally thanthe plane of shaft b, and in locating the position of the rear end oflink l5, this relationship of the two shafts is considered, with suchlink rear end positioned practically on a line connecting the two shaftswhen in this position.

This ar angement is of advantage'through the fact that i swinging thecutting unit, as'presently explained, the radius of such.movement willbe less vthan the distance between shafts b and e in the position aboveindicated, so that the chain connection 126 will not be tightened by theswinging action; in other words, with the rear end of link IS on a lineconnecting the axes of shafts b and e in this particular position shown,the link itself will extend on such line and thuslocates the shaft e atits greatest distance from shaft 0. With the link of shorter length thanthe distance between the shafts in this position, the swinging arctraversed by shaft e will be on a radius less than that of the distancebetween theshafts with the result that in swinging from this positionthe distance between the shafts will tend to decrease,

although the decrease is slight-the difference between arcs based on theaxis of the rear end of link l5 and of shaft 17. Since shafts b and ecarry the sprockets forthe chain connection 178, it can be understoodthat the chain adjustment for the position shown will ensure and permitfree chain drive action during any swinging movement of the cuttingunit; due to the fact that the arcs referred to are almost co-incident,the variation is very slight within the range of the normal swingingmovement, so that there is no material effect on the drive action, anyeffect being in the direction of slackening the chain rather thantightening it as compared with. the

position shown.

As indicated, link 15 extends on a line connect ing the axesof the twoshafts b and e in the position shown, thus placing the link asinclined'to the horizontal. This particular inclination is also providedwith respect to link 16, the two links being in substantial parallelism.To complete the characteristics of a parallelogram, the positions of thefront and rear end connections of link I6 are arranged at substantialright angles to the angle of link l5 to the horizontal in the positionshown. In other words, in the position shown, the

location of. the front end of link lfiabove the axis.v

of shaft e is on a line extending at right angles to the line of link l5and extending through the axis of shaft e. Similarly, in such position,the

tioned relative to the power unit, so that the shaft e will have adefinite swinging path, and at the same time the side members It) willbe held against rotation about shaft 6 excepting as determined by theaction of link l6, the shaft swinging on the axis of the rear end oflink I5 while the rotation of the side members 10 will be determined bythe swinging of the front ends of links IS on the axis of the rear endof such link If). In other words, the front end of each link willtraverse an are individual to itself, but because of the angularity ofthe links in the position shown and the effect of the parallelogramcharacteristics, the line which connects the axes of the front ends ,ofthe links retains substantially the same angularity during the swingingmovements, the position of the front end of link l6 being such that thesmall rotation of the members ID will be due to the shifting of the axisof the front end of link IS on an are which closely approaches thehorizontal during actual service conditions. 7

Thus far, the description of the swinging movement of the cutting unithas been based on the assumption that the mower is stationary, so thatthe rollers A and D preserve the substantially horizontal characteristicof the power plant shown in the drawings; the swinging movements of thecutting unit being considered on the basis of no change in the positionof the rear ends of links or struts l5 and IS, the swinging action beingrestricted to the forward ends of these struts. Under these conditions,there is necessarily a slight change from the exact parallelism of thesides and ends of the parallelogram, during swinging movement-s, due tothe fact that the rear end of the parallelogram remains constant whilethe links change their angles to the horizontal, so that the includedangle at the rear end of a strut changes in value to an extentdetermined by the extent of swing. The parallelism between the strutsmay vary to a slight degree during such movement, since the distancebetween two horizontal planes extending through the axes of,pivotal'movement of the front ends of the struts may vary while thedistance between the planes at the rear ends remains constant, thevariation at the front end being due to the fact that the axis of thefront end of strut or link l6 travels in an arcuate path the center ofwhich is the axis of the front end of strut or link l5.

In other words, the arrangement does not provide the completecharacteristicsof a structure of the parallel ruler type, since, in theposition shown, only the connection at one end is-shifted, so thatparallelism of the links is not necessarily preserved duringthe shiftingmovements,but the variation is of no material amount within reasonablelimits of shifting movement due to the fact that the axis of the fr'ontend of strut I6 is in the top zone of the frame In so that the distancechange between the horizontal planes is changed but slightly as suchaxis swings about theaxis of shaft 6. a However, there is a variationfrom this under actual service conditions. As will be understood, themower travelsas a complete assembly, so that where the ground surface isriot perfectly flat, or

contact is at the base of theslop.

of the undulatory characteristic, the three contactsshoe l4, roller Dand roller A approach the point of change in the ground condition inthat order. For instance, if the change is to an upward slope, the shoel4 firstreaches the point of change and causes the contact unit to swingupwardly along the lines indicated above, the swinging range increasingas the shoe traverses the slope, the limit in this respect being reachedwhen roller D reaches the bottom of the slope. As roller D raises intraversing the slope, the shoe and roller D would have their points ofground contact on the equivalent of the level surface-the surface of theslope-but this fact does not immediately restore the former condition,due to the fact that while the roller D has been raised by the slope,roller A still remains on the level ground. And this fact varies the"operation due to the fact that the variation in position of roller Dnecessarily swings the frame of the power plant around the axis ofroller A, thisswinging continuing until roller -A advances to theposition where its point of ground As roller A also begins to traversethe slope, the three contact points then resume the conditions shown inFig. 1, excepting that the ground line then represents the slope.

When the crest of the slope is reached, the shoe l4 first detects thechange and again begins a cycle of development .such as pointed out, theextent of the swinging movements of the parts depending on whetherthe'crest leads to a level surface, or a downward slope, or even asimple reduction or increase in the angularity of the upward slope. In

other words, the cycle of development of the vari- 5 understood. Sincethe rear axes of the two links 15 and I6 are'fixed in position withrespect to the power unit frame, it can be understood that swingingmovement of the latter frame about the axis of roller A necessarilychanges the positions of these axes relative to a vertical plane. Bothaxes are normally abovev a horizontal plane through the axisof roller A,so that swinging of the power unit frame carries the strut axes in thesame direction relative to such vertical plane, but with the distancechanges varying duev to the vertical spacing of the strut axes, thevariatiomdepending,

of course,on the length of the radii of the swinging action; if thestrut axes were positioned at equal radial distance from the axis ofroller A, the variation would be considerable due to the fact that theaxis of strut I5 is adjacent the horizontal plane through the axis'ofroller A, while the axis of. strut I6 (reference being made to the axesof the rear ends of these struts) is more remote from such plane, scthat the arcs traversed have different relations to a vertical plane. f

However, as indicated in Fig. 1, the radius of the end of strut I6 isgreater than that of strut I5 with the result thatthe arc of travel ofthe axisv of the end of strut I6 is of greater radiusand thereforeflatter so that the distance, change of this axis is not as great as ifthe length ofthe radii were equal. i

When, therefore, roller D begins to traverse the upward slope, swingingof the power unit frame on the axis of roller A causes-the axes of .therear ends of the struts to traverse their respective arcs, both tendingto bring the shoe nearer to the roller D, so that the shaft e would beshifted slightly if the swinging movement were large.

, Since, however, the axisof the front end of strut l6 moves in acircular path relative to shaft e, it can be understood that through thegreater rearward movement of the axis of the rear end of the strut Hi,the movement of the front end of this strut will be greater and in adirection to tend to rock the cutter unit frame counter-clockwise inFig. 1 and thus shift the position of the shoe forwardly, so thatalthough the swinging of the power unit frame would seemingly tend tobring the shoe nearer to roller D, the linkage described serves tocounteract this condition.

A number of possible groundsurface conditions and the effect thereof areshown diagrammatically in Figs. 10 to 15, inclusive. These will indicatevarious effects produced on the cutting unit as the resultant reactionto the movement of the mower over undulating surfaces.

From this it can be understood that the position of shaft e is notmaterially changed from a vertical plane during these various automaticadjustments provided by the swinging of the two units,

strut liapproaching the horizontal, so that the shaft is at the fiattestzone of the arc of movement when the latter is based on. the swinging ofthe cutter unit bodily. And the same is true with respect to the axis ofthe rear end of strut l5 and its location but a short distance above ahorizontal' plane through the axis of roller A; such rear axis is thusinthe flattest zone of its arc' of travel about the axis of roller A,but sufficiently above the horizontal plane so that roller- D may drop aconsiderable distance before the axis of-the rear end of strut l'5 wouldreach the horizontal plane or dead center position.

However, due to the greater distance of dis placement of the axis of therear end. of strut' I6assuming the roller D to be movingipn anupwardslopefrom a. vertical plane, the rocking of the cutter frame bystrut I5 will be afiected to a greater extent, thus effecting a changein the position of the-shoe, with the result that the condi-' tions ofcompensation are taken care of to an extent such as to provide foreificient operation, even in presence of aground surface, excessivelyundulating. 1

While these movements are produced through the relationships set upbetween the two units by the linkage, it can be understood that thedis-'- tance relation between the pivot axes at the opposite ends of alink remains constant in service:

reel axis, strut l5 generally controls the movement of the cutting unitbodily, while strut l6 controls the movement of the cutting blade aboutthe reel axis. B'ut, due to thefact that the relationship of the rearaxes of these struts has the particular relationship to the axis ofroller A, the entire aavsemblage sets up a definite compensating actionthrough the effect of the traction of both units\ over the surface beingoperated upon.

All of the changes set upby the varied positions which the mower mayassume in service are not referred to specifically above, these beingreadily As a result, and due to the fact that determined by consideringthe effects of the changes produced by the illustrations given above.The conditions indicated in the drawings are prescut when the surface islevel, whether that surface correspond with or be inclined to thehorizontal, but these conditions change through the development of ageneral cycle such as referred to above when the surface varies fromsuch level, with the shoe first detecting the change, followed by rollerD and finally ending the cycle when roller A reaches the succeedinglevel. During the cycle period set up by a change in groundcharacteristics, whether the change be produced in an upward or.downward direction, the two units, connected by the substantially rigidlinks or struts, set up various compensating activities through thecombined action of both'units, with the compensating efiect mademanifest at the cutting point. It is possible that the cutting line mayvary slightly during the changes, but the variation if present, is soslight as to be inconsequential, so that the appearance of the mowedground is not affected by its presence.

As indicated in Fig. 5, link l5 has its rear end bent laterally as atl5a;, this bent portion extending through frame B and providing the axisof pivotal movement of the rear end of the link.

The forward end of link I5 is threaded'into a cou-,

pling member l5b carried by shaft e outside of the side member It), thearrangement presenting the ability for adjustment in the length of thelink,

ditions.

Link I6 is=somewhat similar in arrangement, the bent end 16a,however,'extending through the thus permitting for take up in chainlength conspect, being formed in two parts having the' threadedformation which, with a nut I60 will set up the characteristics of aturnbuckle formation to vary the length of the link. The purpose of thisturnbuckle structure is to adjust the. angularity of the cutting knifel3. For instance, if the length of link I 6 is increased, such increasewill rotate the side frame l0 clockwise in Fig. 1, and

thus relatively raise the cross-bar relative to a horizontal planethrough the axis of shaft e but' without changing its distance relationto such Hence, the angle of the cutting knife will shaft. be changed andpermit a deeper cut to be made. If the length of the link be decreasedthe rotation .will be in reversed direction and decrease the depth ofthe cut. Such adjustment will change "the' angularity of the lineconnecting the front ends of the links-since only the position of the'the front of-frame B, with the extensions connected by a cross-rod M.The latter carrieshook members l1, having stops IIa which, with the hookin inactive position, rest on the extensions. The side members In carrya bracket, I 8 having a perforation l8a to receive the hook end. Whenthe cutting unit is swung upwardly, manually or otherwise, the hooks canbe s'wung The arrangement also permits ready positioninto engagementwith the bracket perforations and thus maintain the cutting unit raisedfrom the ground to permit the power unit to travel without the cuttingunit being operative; Fig. 16 shows, diagrammatically, the cutting unitin such raised position; at such time the clutch b2 shown in detail inFig. 9, is in position to disconnect the drive sleeve 135 from shaft b.

The contact surface of the shoe is curvilinear and of convexcharacteristics sothat when shifting of a side member changes theangularity of the plane of the cutting blade, as when reaching a slopeof the mowing path, the shoe permits of the change in height of the lineof cut as to compensate although the angularity of the radius remainssubstantially constant.

While I have herein shown and described a preferred construction andarrangement, it will be readily understood that changes andmodifications therein may be found desirable or essential in meeting theexigencies of service conditions or the desires of users, and I desireto be understood as reserving the right to make any and all such changesor modifications as may be found desirableor essential, insofar as thesame may fall within the spirit and scope of the accompanying claims,when broadly construed.

Having thus described my invention, what I claim as new is:-

1. In a lawn mower, a power unit, a cutting unit including a rotatablecutting reel and a relatively stationary cutting blade co-op'erating toprovide a cutting line of definite distance from the reel axis on aradius extending from such axis, and connections between said-units andeach having individual pivotal relationship with both units andoperative to retain the distance between pivot axes of a connection andthe units constant during service, said connections permitting swingingof the cutting unit bodily in an arcuate path and rotative movement ofthe cutting blade about the cutting reel axis by the traction of theconnected units during service.

2. A mower as in claim 1 characterized in that the cutting blade isadjustable relative to the reel axis to vary the length of such radius.

3. A mower as in claim 1 characterized in that the several connectionsare each rigid between the pivot axes of a connection and the units.

4. A mower as in claim 1 characterized in that the connections at eachside are in pairs with one of the pair connections of fixed .length andthe other connection of the pair adjustable as -to length to vary thedistance characteristic of the pivot axes of such adjustable connectionat will. 5. A mower as in claim 1 characterized in that the cutting unitincludes side members rotative cn and relative to the reel axis, aholder for the cutting blade secured to said members with the holderfixedly positioning the blade in definite plane relation to the holder,said connections I being operative to provide rotative movement to theside members and thereby vary the plane of the blade relative to thehorizontal during movementspf the reel axis in its arcuate path.

6. A mower as in claim 1 characterized in that the, cutting unitincludes side members rotative on and relative to the reel axis, aholder for the cutting blade secured to said'members with the holderfixedly positioning the blade in definite plane relation to the holder,said holder also including a shoe formation adapted to contact thesurface traversed by the mower, with the shoe formation having acurvilinear contact surface of the. convex type, said connections beingoperative to provide rotative movement to the side members duringmovements of the reel axis in its arcuate path to thereby vary the planeof the blade relative to the horizontal and through the curved co actsurface of the shoe formation permit the line of cut to be maintainedsubstantially constant as to depth of cut during such reel axismovement.

7. A mower as in claim 1 characterized in that the power and. cuttingunits carry complemental manually-operated means co-operative to supportthe cutting unit in inactive position when the cutting unit has beenswung upwardly in its arcuate path a definite distance.

8. A mower as in claim 1 characterized in that the power unit carries apair of pivoted hooks, and the cutting unit includes side memberseachcarrying a member co-operative with one such hook to support the cuttingmember in inactive position, the hooks and members being positioned tobe brought into co-operative relation when the cutting unit has beenswung upwardly in its arcuate path to a definite inactive position. I

9. In a lawn mower, a power unit; a cutting unit including arotatablef'cutting reel, a relatively stationary cutting blade, and sidemembers for supporting the reel and blade with the members rotative onand relatively to the reel axis; and connections between the power andcutting units and each having individual'pivotal relationship with bothunits and operative to retain the distance between the pivotaxes of aconnecwith the power unit, the point of connection of the latter linkwith its member being above and spaced from the reel axis.

10. A mower as in claim 9 characterized in that the pair of links extendin substantial parallelism.

11. A mower as in claim 9 characterized in that the point of connectionof the second link with its member is forward of a vertical planecorresponding to and extending through the reel axis when the cuttingunit is in mowing position. 12. A mower as in claim 9 characterized inthat the pair of links and their points of connection with the unitssubstantially present characteristics of a parallelogram, I

13. A mower as in claim 9 characterized in that the second link isadjustable as to length.

14. A mower as in'claim: 9 characterized in that the pairof links extendin substantial parallelism with the first link of substantially con-'stant length and the second link adjustable in length.

15. In a lawn mower, a power unit including a tive on and relatively tothe reel axis; drive connections between the drive shaft and reel shaft;

and connections between the power and cutting units and each havingindividual pivotal relationship with both units to retain the distancebetween the pivot axes of a connection and the units constant duringservice to permit bodily swinging of the cutting unit in an arcuate,path, said connections including a link connecting-the reel shaft withthe power unit frame, the point of connection with the frame beingadjacent to the drive shaft but intermediate said drive and than thedistance between said shafts, and a second link connecting a side memberwith the power unit frame, the point of connection of the second linkand" its side member being above and spaced from the reel axis.

16. A mower as in claim 15 characterized in that the links extend insubstantial parallelism. 17. A mower as in claim 15 characterized inthat the links extend in substantial parallelism and inclined forwardlyto the horizontal when the power and cutting units are traversing ahorizontal mowing path.

18. A mower as in claim 15 characterized in that the second link isadjustable in length.-

such as to cause the links and the parts to which 10 they are secured tosubstantially present characteristics of a parallelogram;

HAROLD L. BLYDENBURGHL-

